Fundimentals of GIS - Exam 1 Study Guide

Geographic Information Systems

GIS: system that capture, store, manipuate, visulize geoggraphic data

Urba planning

Enviormental management

Agriculture

Transportation

Public heath

ESRI/ArcPRO

Software in GIS -

ESRI develops GIS tools

ArcPro latest desktop GIS software

Physical entity

actual geographic object

spatial object

identifiable entities in space characterized by specific attributes, boundaries, and processes

cartographic object

computer representation of a physical entity

thematic layers

Contains all fo the same “type of data”
later for river, layer for roads, layer for elevation

cartesian coordinate system

Two-three dimensional grid system using linear distances (X-axis= hori, Y-axis = vert)

geographic coordinate system

GCS - global reference system that defins location using ANGLES
degreese, minuents(‘), and seconds (“) or decimla degrees

Uses latitude and longitude

attribute data

Non-spatial data about spatial objects (names, values, numbers)

vectors

Model with points, lines, and polygons (roads, streams, points)
LINES HAVE NO DIMENSIONS

CAN: store spatial relationship + high precision graphs + support tradiitional cartography

CANT: difficult to update, complicated file strucutres

rasters

Grid cells to represnt a region (aerial/topographic maps) each cell is a value (square cel)

• Can be both discrete + continute data

CAN” simple, easy spatial analysis

CANT: file very large, pixleated if close

USGS quadrangle

Very common (1:24000), covers around 7.5 min rectangle. Elevation derived from pairs of air photos.

contour lines

Lines that show elevation on a map (closer lines = stepper slope)

If lines cross stream, V’s in contour line point upstream

map scale

ratio of distance on the map corresponding to the distance on the ground

discrete data

Clearly bounded features, SHARP BOUNDARIES, roads, land, houses

continuous data

Values change contunously across surface (gradient, elevation, temp)

resolution

Level of detail in spatial data

Raster = pixel sixe

Vector = cordinate precision + gemogetry detail

dataframe

container that holds one or more layers of spatial data (vector/raster), organizes how it looks

inclusion/generalization errors

Vector: feature incorrectly included/excludede in a dataset (present or absent)

mixed pixel problem

Raster: pixel contain mutiple land over types but raster shows one value

Nominal Attributes

Descriptive information (text, words, color, names)

Ordinal Attributes

Ranking (text or number)

Interval/Ratio Attributes

numbers (area, height, weight)

MATH DD from DMS (EX) DMS = 32°45’28’

DD = D + M/60 + S/3600

32 + 45/60 + 28/3600

=32 + 0.75 + 0.0077778

=32.7577778

MATH DMS from DD (EX) DD = 24.93547

D = ineger part

M = integer of decimal part X 60

S = 2nd decimal x 60

D=24

M = 0.93547 × 60 = 56.1282

M = 56

S = 0.1282 × 60 = 7.692

24°,56’,7.692’

Datum

mathematical model of the Earth (many cuz each about specific stuff)

Projection

Different ways to flatten Earth so it can be seen
distort in Area Direction Shape Distance

Geoid

Three dimensional surface along which the pull of gravity is a constant

Ellipsoid

Modle of Earth - flat at poles an round at equator

Prime meridian

starting line for longitude in GIS

UTM

UTM is a meter-based projected coordinate system that divides the Earth into zones to minimize distortion (global)
Zones are numbered 1–60, starting at 180°W
Zone number (1–60)

• Hemisphere (N or S)

units meters

State Plane

State Plane is a high-accuracy, U.S.-specific coordinate system designed for surveying and engineering.

-meters